The present invention relates to catheters for endocardial biopsy.
The term "biopsy" generally means the removal of a fragment of living tissue for diagnostic purposes. An endocardial biopsy is currently carried out in cases of suspected myocarditis or cardiomyopathy. According to conventional techniques, the biopsy is carried out by means of a catheter the distal end of which carries sampling forceps. This distal end is made to enter the heart through a blood vessel under X-ray or echographical control. Currently, an endocardial biopsy is performed on patients who already have obvious signs of myocarditis or cardiomyopathy, in order to confirm the diagnosis. It would be desirable, however, to be able to use endocardial biopsy for the timely identification of the existence of a cardiomyopathy or myocarditis when the patient does not yet have obvious signs. There are, for example, apparently healthy patients in whom ventricular arrhythmia in turn precedes the manifestation of obvious signs of myocarditis or cardiomyopathy. In these cases, an endocardial biopsy could enable early diagnosis, provided that it were possible to take tissue samples with certainty, both in correspondence the zone of origin of the arrhythmia and in correspondence with zones remote therefrom. It would therefore be necessary to be able precisely to identify the point of origin of the arrhythmia immediately before the sampling is carried out at that point.
Catheters of various types are already known (see, for example, U.S. Pat. No. 4,649,924, assigned to the same Applicant) which are provided with electrodes that can detect the electrical potential at various points on the heart wall, so as to enable the point of origin of the arrhythmia to be identified. In theory, therefore, it should be possible to insert firstly a catheter of this type for the detection of the origin of the arrhythmia and secondly the catheter for the biopsy. However, this manner of operation has the disadvantage that it takes a very long time, with adverse consequences for the patient, and is in any case not very reliable since it is difficult to ensure that the tissue sampling is carried out exactly in correspondence with the zone identified as the origin of the arrhythmia.